Sunan Ibn Majah
1177
Sahih+2

It was narrated that ‘Aishah said:“The Messenger of Allah (ﷺ) used to say Taslim after every two Rak’ah, and he would perform Witr with one Rak’ah.”

SahihMuhammad Fouad Abd al-Baqi
SahihShuaib Al Arnaut